メキシココガラ Poecile sclateri

The only chickadee in its range: primarily occurs in northern and central Mexico, barely entering the U.S. in the Chiricahua and Animas Mountains. Darker gray body than other chickadees, with black cap, white cheeks, and extensive black throat. Lacks any warm buffy tones. Restricted to mountainous pine forests, often in mixed flocks with other small songbirds. Listen for rather complex gurgling song and harsh call notes.